vue实现倒计时功能

<div class="itemend">
 <p class="itemss">倒计时<span>{{day}}</span>天<span>{{hour}}</span>时<span>{{minute}}</span>分<span>{{second}}</span>秒</p>
</div>

data() {
 return {
 day: "", //天
 hour: "", //时
 minute: "", //分
 second: "", //秒
 flag: false,
 };
 },
 mounted() {
 let time = setInterval(() => {
 if (this.flag == true) {
 clearInterval(time);
 }
 this.timeDown();
 }, 500);
 },
 props: {
 endTime: {
 type: String,
 },
 },
 methods: {
 timeDown() {
 const endTime = new Date(this.endTime);
 const nowTime = new Date();
 let leftTime = parseInt((endTime.getTime() - nowTime.getTime()) / 1000);
 let d = parseInt(leftTime / (24 * 60 * 60));
 let h = this.formate(parseInt((leftTime / (60 * 60)) % 24));
 let m = this.formate(parseInt((leftTime / 60) % 60));
 let s = this.formate(parseInt(leftTime % 60));
 if (leftTime <= 0) {
 this.flag = true;
 this.$emit("time-end");
 }
 this.day = d; //天
 this.hour = h; //时
 this.minute = m; //分
 this.second = s; //秒
 },
 formate(time) {
 if (time >= 10) {
 return time;
 } else {
 return `0${time}`;
 }
 },
}

<template>
 <div>
 <Times :endTime='timeEnd'></Times>
 </div> 
</template>

import Times from "@/components/time";
export default {
 name: "Home",
 data() {
 return {
 timeEnd: "2021-3-30 9:50" //结束时间(苹果手机无法解析"-" 可以将格式改为2021/3/30)
 },
 
 components: {
 Times,
 },
};